Starting and stopping mechanism



Feb. 13, 1923.

W. ARTER STARTING AND STOPPING MECHANISM Fj 1 ed Oct. 27, 1919 2' sheets-sheet 1 Feb. 13, 1* 23. 1,445,283 W. ARTER STARTING AND STOPPING MECHANISM Filed Oct. 27, 1919 2 sheets-sheet 2 VE/V TU/ii v M4 4; 5; M

WILLIAM ARTEB, OF WORCESTER, MASSACHUSETTS.

STAB/TING AND STOPPING MECHANISM.

Application filed October 27, 1919. Serial No. 333,821.

To a]? whom it may concern: Fig. 3 is a bottom view of the moving lie it known that i, ll iniinirr .iin'rnn, a parts of the brake mechanism provided by subject of the King of (treat Britain, residthis invention; and iup at Worcester, in the county of orccstol ig. l is a view of certain parts shown in 5 d dr g f klag mhusetts, have invented li ipj. 3 but showing these parts in a different certain improvements in Starting and Stopposition. ping cz hanisms, of which the following dein the drawings, 2 designates a magnetic scription, in connection with the accompany chuck mounted on the upper end of a verti- 60 inc drawings, is a specification, like refcrcal shaft 3, the weight of these parts being once characters on the drawings indicating supported by conical bearing members 4 like parts in the several figures. and 5. Another bearing 6 guides the lower This invention relatesito starting and stopend of the shaft. These parts are all pin; mechanisms for machines and is parmounted in a bracket 7 which is supported ticularly concerned with a mechanism of 011 a pivot pin 8 carried by a slide. 9 that may this type designed to meet the requirements be adjusted vertically by a suitable elevatin i of grinding machines equipped with a to mechanism. as will be readily understood by tary chuck supported on a vertical shaft. those skilled in this art. The pivotal sup It is usual to equip machines of this type port of the bracket 7 enables it to be ad- F with some form of clutch to control the to justed angularly to suit the nature and retation of the chuck shaft, and since the to quirements of the work.

tating parts are very heavy, their momentum The bracket 7 is hollowed out to receive will cause them to rotate for a long time a stationary brake sleeve or drum 10 and the after the shaft has been disconnected from inner surface of this drum is machined to its source of power unless some kind of a co-operate with the peripheral surface of a 25 brake mechanism is provided to stop it. It split brake ring 12, best shown in Fig. is the chief object of the present invention From this figure it will be seen that this to devise a starting and stopping mechanism ring has two concentric ring portions, the which will satisfy the peculiar requirements outer ring 12 being split to form two end as to space limits in machines of this type, portions a and Z), and the inner portion 14:

30 which can be economically manufactured, closely embracing the shaft 3. At what may wiil not be subject to rapid wear or deteriobe termed the frontside, the inner and outer ration, will be reliable in operation, and will sections of the ring are separated by a saw be convenient for the workmen to operate. cut 15, while the rear side these sections Whilethe invention is directed particularly are connected by a web 16 which is drilled 35 to the requirements of grinding machine to receive a set screw 17 by means of which chuck shafts, it will be evident that the the split ring is secured fast to the chuck mechanism provided by this invention is apshaft 3. plicable also to other machines. The opposite walls of the split in the ring The nature of the invention will be readily 12 are recessed to receive projections 18 and 40 understood from the'following description 19, respectively, that extend upwardlytfrom when read in connection with the accomthe respective levers 20 and 2-1. These levers panying drawings and the novel features are curved, as clearly shown in 3, and will be particularly pointed out in the aphave knobs 22 and 23, respectively, secured pended claims. to their free ends and located at substan- 45 Referring now to the drawings: tially diametrically opposite points where Figure- 1 is a vertical cross sectional view they may be engaged and spread apart by through those parts of the grinding mathe upper bevelled end of a sleeve 24L, Fig. 1, chine immediately associated with a chuck mounted to slide longitudinally of the shaft shaft; It will be seen from an inspection of 5 Fig. 9. is a. side elevation of the parts of Figs. 3 and 4 that the projections 18 and 19 a grinding machine adjacent to the chuck, are rounded cylindrical pins cut away certain of the parts being broken away 5. form flattened faces that normally lie in contact with each other. When the sleeve 24 is moved upwardly and spreads the free ends of the levers 20 and 21, apart, it rocks these faces about their forward edges as a fulcrum, moving them into a position substantially as shown in Fig. 4, and thus spreads the ends a and b of the friction ring 12 apart expanding this ring into engage ment with the inner surface of the stationary brake drum 10. This obviously applies a powerful braking action to the shaft and stops its rotative movement quickly. When the sleeve 2-4: is lowered again out of contact with the knobs 22 and 23 on the levers 20 x and 21, respectively, the ring 12 contracts due to its inherent elasticity. returning to its initialposition, as shown in Fig. 3, and thus swings the lovers back into the position shown in said figure. This action is aided by a spring 25 which connects the ends a and b of the split ring.

In order to hold the levers 20 and 21 in their operative positions, a pin 26 is threaded into the inner section 1 1- of the friction ring and lies in recesses formed in the opposite faces of the parts a and Z) and 18 and 19. There is very little tendency for the levers to drop out of their normal positions since the projections 18 and 19 are constantly gripped by the ends a and 7) of the split ring, but this slight tendency is effectually resisted by the engagement of these parts with the pin 26. i v

The sleeve 2 1- may be moved up and down in any convenient manner, as, for instance, by means of a bifurcated lever arm 27, Fig. 1, carrying rolls that enter a slot 28 forming the periphery of the sleeve 2a, the lever being mounted fast on a rock shaft 29 which projects through the housing or casing 30 and has a hand lever 31 fixed thereto at a point outside of said housing.

For the purpose of driving the shaft a gear 32 is mounted loosely thereon, the weight of the gear being supported by a collar 33, Fig. 1., secured to the shaft. This gear is hollowed out to receive a split ring 34-, like the ring 12 in construction, which is keyed to the shaft 3 and co-operates with a pair of levers like the levers 20 and 21.

One of these levers is indicated in Fig. 1, at

35. These parts form an expanding clutch of exactly the same construction as the expanding brake above described, the only difference being that the expanding clutch ring 34: engages the inner surface of the gear 32, whereas the expanding brake ring 12 engages the inner surface of the brake drum 10. The lower end of the sleeve 24 is bevelled so that it operates on the levers that expand the ring 34 in the same way that it operates on the levers 20 and 21. This arrangement is of advantage in manufacturing and assembling since it reduces the number of kinds of parts required, the

parts of the clutch being duplicates of those of the brake with. the exception above mentioned.

It will also be seen that this construction is exceedingly simple to manufacture, that it forms a very effective and reliable construction of brake and clutch, that it can be conveniently operated by a single actuating member, and that it is well adapted for use in. the small space limits within which these parts must be located in grinding and similar machines.

It is obvious that many changes may be made in details of the construction shown wil'lunit departing from the spirit or scope of this invention. For instance, instead of using the brake druni 10 the braking surface could be formed directly in the bracket '1' without in any wise modifying the OPGIZ tion of the mechanism. This, however, is regarded as an equivalent construction.

What is claimed as new is:

1. In. a machine of the character described, the combination of a rotatable shaft, a bearing bracket supporting said shaft, a driving gear for said'shaft loosely mounted thereon and having a recess therein, an' expanding clutch including a clutch member secured to said shaft and located in said recess,'a stationary brake drum encircling said shaft and supported by said bracket, an expansible brake comprising a brake member located within said drum and secured to said shaft, operating means for said brake and clutch including asleeve mounted between said brake and clutch for operating either of them, and means for sliding said sleeve on said shaft.

2. In a machine of the character described, the combination of a rotatable shaft, a bearing bracket supporting said shaft, a driving gear for said shaft loosely mounted thereon and having a recess therein, a split clutch ring fast on said shaft'and located within said recess, a pair of levers cooperat ing with the split in said ring to expand the ring into engagement withthe walls of-the recess in said gear, said levers having ends lying closely adjacent to said shaft, a sleeve slidable longitudinally of said shaft and having a bevelled end to engage the ends of said levers to operate them and thereby ex pand said clutch ring, a stationary brake drum encircling said shaft and supported by said bracket, a split brake ring secured to said shaft and mounted within said drum, a second pair of levers like the levers above mentioned arranged to expand said brake ring into engagement with said brake drum and positioned to be operated by said sleeve,

and means for sliding said sleeve longitudinally of said shaft.

In testimony whereof I have signed my name to this specification.

lVILLTAM ARTER. 

